Flow-through heater

ABSTRACT

A flow-through heater includes a tubular housing and a heating element. The tubular housing defines a passageway. The heating element is provided in the passageway and attached to the tubular housing. The heating element includes a resistive wire and an electrically insulating coating on the resistive wire. The heating element includes a coiled wire portion coiled along a longitudinal axis of the tubular housing. The coiled wire portion defines a channel extending in a direction along the longitudinal axis to enable a fluid to flow therethrough. The coiled wire portion contacts the fluid when the fluid flows through the channel.

FIELD

The present disclosure relates to a fluid heater for an appliance. In particular, the present disclosure relates to an improved construction for a flow-through heater for heating water or other liquids and/or generating steam.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Appliances, such as dishwashers, clothes washers and water heaters, for example, employ a heater for heating water or other liquid that is used in the appliance. One type of heater used is a flow-through heater. An exemplary prior art flow-through heater is shown in FIG. 1. The flow-through heater 10 includes a hollow, metal, cylindrical member 12 having a passageway 14 extending along its longitudinal axis 16 through which water or other liquid to be heated flows. An electric heating element 18 is generally spirally-wrapped around the circumference of the cylindrical member 12 for a length along its longitudinal axis 16. Typically the cylindrical member 12 is made from stainless steel and the electric heating element 10 is brazed or crimped to an exterior surface of the cylindrical wall 24.

Mounted at locations on the exterior surface of the cylindrical member 12 are one or more temperature sensor assemblies 20 and 22. The temperature sensor assemblies 20 and 22 can house a temperature sensor, like a thermostat device or NTC device. In the example shown in FIG. 1, one temperature sensor assembly 20 provides an electrical connection to a power source for the heating element 10 and includes a thermostat. Another temperature sensor assembly 22 carries an NTC temperature sensor.

The electrical heating element 18 generates heat that is transferred to the cylindrical member 12 and, ultimately, to the fluid passing through the heater 10. A control system (not shown) regulates the temperature of the heating element 10 and/or fluid passing through the heater 10 based on feedback from the temperature sensor assemblies 20 and 22. A shroud 24 is located over the heating element 18 to cover and protect the heating element 18 and shield the surrounding area from the heating element 18.

Conventional flow-through heaters like that shown in FIG. 1 have a heating element that is brazed to the cylindrical member 12. Brazing the heating element 18 to the cylindrical member 12 ensures proper contact between the heating element 18 and the outer surface of the cylindrical member 12 and consequently optimum heat transfer from the heating element 18 to the cylindrical member 12 and the fluid flowing therethrough. Brazing the heating element 18, however, is time consuming due to the spirally-wrapped structure of the heating element 18. Moreover, the heating element 18 may have a slow response in heating the fluid due to indirect heating and/or heat loss to the cylindrical member 12.

SUMMARY

A flow-through heater of the present disclosure includes a tubular housing and a heating element. The tubular housing defines a passageway. The heating element is provided in the passageway and attached to the tubular housing. The heating element includes a resistive wire housed within an electrically insulating coating. The heating element includes a coiled wire portion defining a channel extending in a direction along a longitudinal axis of the tubular housing. The coiled wire portion defines a channel extending along the longitudinal axis to enable a fluid to flow therethrough. The coiled wire portion contacts the fluid when the fluid flows through the channel.

A flow-through heater of the present disclosure includes a metal cylindrical wall, a plurality of metal fin elements, and a heating element. The metal cylindrical wall includes an inner peripheral surface. The inner peripheral surface defines a passageway along a longitudinal axis of the cylindrical wall. The plurality of metallic fin elements extend inwardly from the inner peripheral surface and are located in the passageway. The heating element is provided on an outer peripheral surface of the metallic cylindrical wall.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

FIG. 1 is a front perspective view of a prior art flow-through heater;

FIG. 2A is a front perspective view of a flow-through heater according to a first embodiment of the present disclosure;

FIG. 2B is a front cross-sectional perspective view of a flow-through heater according to a first embodiment of the present disclosure;

FIG. 3 is an enlarged, partial end view showing a connection between a tubular housing and an insulator of the flow-through heater according to the first embodiment of the present disclosure;

FIG. 4 is an enlarged, partial cross-sectional view showing a connection between a terminal assembly and a tubular housing of a heater according to the first embodiment of the present disclosure;

FIG. 5 is a front perspective view of a flow-through heater according to a second embodiment of the present disclosure;

FIG. 6A is a front cross-sectional perspective view of a flow-through heater according to a second embodiment of the present disclosure;

FIG. 6B is an end view of a flow-through heater according to a second embodiment of the present disclosure;

FIG. 7 is an enlarged, partial cross-sectional view showing connection between a tubular housing and an electrical heating element of a flow-through heater according to a second embodiment of the present disclosure;

FIG. 8 is a perspective view of a flow-through heater according to a third embodiment of the present disclosure;

FIG. 9 is an exploded perspective view of a flow-through heater according to a third embodiment of the present disclosure;

FIG. 10 is an exploded perspective view of a flow-through heater according to a third embodiment of the present disclosure;

FIG. 11 a partial cross-sectional perspective view of a flow-through heater according to a fourth embodiment of the present disclosure;

FIG. 12 is a perspective view of a flow-through heater according to a fifth embodiment of the present disclosure;

FIG. 13 is a cross-sectional perspective view of a flow-through heater according to a fifth embodiment of the present disclosure;

FIG. 14 an end view of a flow-through heater according to a fifth embodiment of the present disclosure;

FIG. 15 is a perspective view of a flow-through heater according to a sixth embodiment of the present disclosure;

FIG. 16 is an exploded perspective view of a flow-through heater according to a sixth embodiment of the present disclosure;

FIG. 17 is an end view of a tubular housing of a flow-through heater according to a sixth embodiment of the present disclosure;

FIG. 18 is a side view of a heating assembly of a flow-through heater according to a sixth embodiment of the present disclosure; and

FIG. 19 is a perspective view of a flow-through heater according to a seventh embodiment of the present disclosure.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Where applicable, corresponding reference numbers are used in the several Figures to identify like components.

First Embodiment

Referring to FIGS. 2A and 2B, a flow-through heater 40 according a first embodiment of the present disclosure generally includes a tubular housing 42, an electrical heating element 44 provided inside the tubular housing 42, and a pair of terminal assemblies 46 mounted on the tubular housing 42. The tubular housing 42 extends along a longitudinal axis 50 and includes a cylindrical wall 52 and a support member 53 provided inside the cylindrical wall 52. The support member 53 includes a pair of fin elements 54 in the present embodiment. The cylindrical wall 52 defines a passageway 56 extending along the longitudinal axis 50 to enable a fluid to flow therethrough.

The fin elements 54 extend radially inwardly from an inner surface of the cylindrical wall 52. The fin elements 54 extend a predetermined length along the longitudinal axis 50 to support and position the heating element 44 in the passageway 56. The fin elements 54 may be integrally formed with the cylindrical wall 52 or attached to the cylindrical wall 52 by any securing means known in the art. The fin elements 54 and the cylindrical wall 52 may be formed of the same material, for example, aluminum, in one molding process. Alternatively, the fin elements 54 may be made of a material different from that of the cylindrical wall 52 and attached to the cylindrical wall 52 by any conventional securing means, such as welding or riveting.

The heating element 44 includes a coiled resistance wire and an electrically insulating coating 59 (shown in FIG. 4) over the wire surface to electrically insulating the resistance wire. The resistance wire may be made from metals such as Fe/Cr/Al or Ni/Cr. The electrically insulating coating 59 may include a corrosion-resistant, thermally conductive material. The materials for the electrically insulating coating 59 include, but are not limited to, epoxy, polyester, polyurethane, polyamide, polyimide, polyethersulfone (PES), polysulfone (PSU), and polyphenylsulfone.

The heating element 44 includes a coiled wire portion 57 and a pair of connecting portions 58. The coiled wire portion 57 includes a plurality of turns, each turn adjacent to one another to form a compact structure. Therefore, heat generated per unit length of the heating element 44 is increased as opposed to prior art heaters under similar operating conditions. The coiled wire portion 57 defines a channel therein and extends a predetermined distance along the length of the fin elements 54. The channel is coaxially aligned with the passageway 56 of the cylindrical wall 52. The pair of connecting portions 58 extend from opposing ends of the coiled wire portion 57 and connect the heating element 44 to an external power source (not shown).

An insulator 60 is provided between the heating element 44 and each of the fin elements 54 to insulate the heating element 44 from the fin elements 54. In addition to the electrically insulating coating 59 of the heating element 44, the insulators 60 provide further electrical insulation for the heating element 44.

Referring to FIG. 3, the insulators 60 may be attached to the fin elements 54 in a snap-fit manner or in a sliding engagement. The insulators 60 each include a receiving portion 62 and a pair of clamping legs 64. Each of the receiving portions 62 includes a base portion 61 extending along the longitudinal axis 50 of the tubular housing 42 and a pair of fingers 63 provided at longitudinal ends of the base portion 61. The base portion 61 and the fingers 63 engage and receive the coiled wire portion 57 of the heating element 44 therebetween. The clamping legs 64 extend along the longitudinal axis 50 of the tubular member 42 and define a slot 65 for receiving a head 67 of the fin element 54. The clamping legs 64 are secured to the respective one of the fin elements 54 by inserting the head 67 into the slot 65. For example, the heads 67 may be inserted into the slot 65 in a snap-fit manner along a radial direction relative to the cylindrical wall 52. Alternatively, the insulators 60 may be attached by sliding the heads 67 into the slots 65 along the longitudinal axis 50 of the cylindrical wall 52. While the clamping legs 64 are shown to extend along the entire length of the base portion 61, it is understood and appreciated that a plurality of clamping legs 64 may be formed at an interval along the length of the base portion 61.

Referring to FIG. 4, the terminal assemblies 46 are inserted through openings 69 of the cylindrical wall 52 and connect the heating element 44 to an external power source (not shown). The terminal assemblies 46 each include a terminal housing 66 and a terminal pin 68 inserted through the terminal housing 66. The terminal housing 66 is made of an electrically insulating material. A cavity 70 is defined at an end of the terminal housing 66 that is located inside the cylindrical wall 52. The terminal pin 68 includes a contact end 72 extending into the cavity 70. The connecting portions 58 of the heating element 44 each include a contact end 74 extending through the terminal housing 66 and into the cavity 70. The contact ends 74 of the heating element 44 are not coated by the electrically insulating coating 59. The contact end 72 of the terminal pin 68 contacts the contact end 74 of the heating element 44 in the cavity 70 to establish electrical connection between the heating element 44 and the terminal pins 68.

The contact ends 72 of the terminal pins 68 are soldered to the contact ends 74 of the heating element 44 to ensure proper contact and electrical connection. A potting material 76 may fill in the cavity 70 after the soldering process to embed and insulate the contact ends 74 of the heating element 44 and the contact ends 72 of the terminal pins 68 therein.

The heater 40 according to the first embodiment of the present disclosure has a quick response and an improved heat transfer efficiency. The heating element 44 is located in the passageway 56. Fluid, which enters the passageway 56, flows around the heating element 44 and is in direct contact with the heating element 44. The fluid flows inside and outside the coiled wire portion 57. Heat generated by the heating element 44 is directly transferred to the fluid. No additional component is located between the heating element 44 and the fluid to absorb heat energy. Therefore, heat transfer efficiency of the heater 40 is improved. Moreover, the heating element 44 can be more easily attached to the tubular housing 42 by using the fin elements 54 and the insulators 60 without time-consuming welding process. Therefore, manufacturing process becomes easier, resulting in reduced manufacturing costs and increased throughput.

Second Embodiment

Referring to FIGS. 5, 6A and 6B, a heater 80 according to a second embodiment of the present disclosure includes a tubular housing 82 and a heating element 84. The tubular housing 82 includes a cylindrical wall 86, a support member including a plurality of fin elements 88, and a pair of hollow portions 90. The cylindrical wall 86, the fin elements 88 and the pair of hollow portions 90 are integrally formed from a polymer material. The cylindrical wall 86 defines a passageway 87 along the longitudinal axis 89.

The fin elements 88 extend from an inner surface 85 of the cylindrical wall 86 for supporting and positioning the heating element 84 in the passageway 87. The fin elements 88 each include an elongated body 89 and a pair of lateral fingers 91 extending laterally from the elongated body 89. The heating element 84 is provided between and clamped by the lateral fingers 91. The tubular housing 82 is made from a polymer material. Therefore, the heating element 84 can be directly placed on the fin elements 88. Because the fin elements 88 are made of an electrically insulating material, the heating element 84 can be attached directly to the elements 88. The number of components that form the heater 80 may be further reduced, resulting in a more simplified structure.

Referring to FIG. 7, the hollow portions 90 extend radially outwardly from an outer surface 92 of the cylindrical wall 86 and are integrally formed with the cylindrical wall 86. The hollow portions 90 are used as terminal housings and each define a cavity 94. The connecting portions 96 of the heating element 84 extend through the cavity 94 and the hollow portions 90 to connect to an external power source. A potting material 76 may fill the cavity 94 to secure the connecting portions 96 of the heating element 84 to the hollow portions 90.

Third Embodiment

Referring to FIGS. 8 to 10, a heater 100 according to a third embodiment of the present disclosure includes a tubular housing 102, a heating element 104, a pair of terminal assemblies 105, a fuse assembly 106, a temperature sensor assembly 108, and a pair of securing members 110.

The tubular housing 102 includes a first part 112 and a second part 114 that jointly define a cylindrical shape and a passageway 116. The first part 112 and the second part 114 are made of a plastic material. The first part 112 defines two openings 120 for receiving the fuse assembly 106 and the temperature sensor assembly 108. An aluminum material is molded to the first part 112 of the tubular housing 112 in the openings 120 to provide an aluminum contact surface 121. A fuse (not shown) of the fuse assembly 106 and a temperature sensor (not shown) of the temperature sensor assembly 108 are provided at the aluminum contact surface 121. The temperature sensor may be a thermostat or an NTC device.

The fuse assembly 106 is mounted adjacent to an inlet of the passageway 116 and upstream from the heating element 104. The temperature sensor assembly 108 is mounted adjacent to an outlet of the passageway 116 and downstream from the heating element 104. The fuse assembly 106 and the temperature sensor assembly 108 each include a casing 122 and a pair of terminals 124 attached to the casing 122. The terminals 124 connect the fuse or the temperature sensor to a power source or a control device (not shown).

The casings 122 of the fuse assembly 106 and the temperature sensor assembly 108 each define a slot 123. The securing members 110 are in the form of a strap positioned in the slots 123 and wrapped around the tubular housing 102. The securing members 110 press the casings 122 of the fuse assembly 106 and the temperature sensor assembly 108 against the aluminum contact surface 121. As such, the fuse and the temperature sensor can contact the aluminum contact surface 121 to ensure proper detection of the temperature of the tubular housing 102 and the fluid flowing therethough.

Referring to FIG. 10, the first part 112 further includes a pair of hollow portions 116 integrally formed with the first part 112 and between the fuse assembly 106 and the temperature sensor assembly 108. The hollow portions 116 each define a cavity 122. A terminal pin 125 is molded to each of the hollow portions 116 to form the terminal assembly 105. The terminal pins 125 each have a contact end 119 extending into the cavity 122 of the respective one of the hollow portions 116. The terminal pin 125 connects the heating element 104 to an external power source (not shown). A potting material may be provided in cavities 122 of the hollow portions 116 to insulate the contact ends 119 of the terminal pins 125 and the contact ends 117 of the heating element 104. Similar to the second embodiment, the heating element 104 may be attached to the tubular housing 102 by a pair of fin elements 131.

The two-piece structure of the tubular housing 102 facilitates soldering of the contact ends 117 of the heating element 104 to the contact ends 119 of the terminal pins 118. The two-piece structure also facilitates mounting of the heating element 104, the fuse assembly 106 and the temperature sensor assembly 108 to the tubular housing 102.

After the heating element 104, the fuse assembly 106, and the temperature sensor assembly 108 are mounted, the first part 12 and the second part 114 of the tubular housing 102 are joined, for example, by high frequency welding.

Fourth Embodiment

Referring to FIG. 11, a heater 126 according to a fourth embodiment of the present disclosure includes a tubular housing 125 having a cylindrical wall 127 and a heating element 128. The cylindrical wall 127 is made of stainless steel. The heating element 128 includes a coiled wire portion defining an outside diameter substantially equal to the inside diameter of the cylindrical wall 127. The heating element 128 is mounted inside the cylindrical wall 127 in an interference-fit manner and is in direct contact with an inner surface 129 of the cylindrical wall 127. The heating element 128 is coated with an electrically insulating coating to electrically insulate the heating element 128 from the cylindrical wall 127 and the fluid flowing therethrough.

While not specifically shown in FIG. 11, a pair of terminal assemblies may be provided at the tubular housing 125 to connect the heating element 128 to an external power source. The terminal assemblies may have a structure similar to that in the first embodiment shown in FIGS. 2A to 4.

Fifth Embodiment

Referring to FIGS. 12 to 14, a heater 130 according to a fifth embodiment of the present disclosure includes a tubular housing 132 and a heating element 134. The tubular housing 132 includes a cylindrical wall 136 and a support member comprising a plurality of fin elements 138 extending inwardly from an inner peripheral surface 139 of the cylindrical wall 136. The plurality of fin elements 138 are shown in the drawings and spaced apart equally (e.g., 3 fin elements at 120° apart) along the inner peripheral surface 139 of the cylindrical wall 136. The cylindrical wall 136 and the fin elements 138 may be integrally formed from a plastic material in one molding process.

The fin elements 138 jointly define a receiving space 141 (indicated by dashed line) for receiving the heating element 134 therein. The heating element 134 may be slid into the receiving space and supported by the fin elements 138. The heating element 134 includes a coiled wire portion 140 and a pair of connecting portions 142. The connecting portions 142 may extend through the cylindrical wall 136 of the tubular housing 132 to be connected to an external power source (not shown). Similarly, the heating element 134 is covered with an electrically insulating coating to insulate the heating element 134.

The cylindrical wall 136 defines a passageway 137. The passageway is generally divided by the coiled wire portion 140 into a first channel 144 and a plurality of second channels 146. The first channel 144 is surrounded by the coiled wire portion 140. The second channels 146 are defined by adjacent fin elements 138 and the outer surface of the coiled wire portion 140. Fluid flows in the first channel 144 and the plurality of second channels 146.

Sixth Embodiment

Referring to FIGS. 15 to 18, a heater 150 according to a sixth embodiment of the present disclosure includes a tubular housing 150, a heating assembly 152, a pair of terminal assemblies 154, a fuse assembly 156, and a temperature sensor assembly 158. The tubular housing 152 includes a cylindrical wall 160 and two hollow portions 162 extending outwardly from an outer surface 157 of the cylindrical wall 160. The cylindrical wall 160 defines a passageway 161 extending along a longitudinal axis 163 of the cylindrical wall 160.

The fuse assembly 156 and the temperature sensor assembly 158 are inserted into the hollow portions 162 and provided downstream from the terminal assemblies 154. A connector housing 159 receives a terminal 161 from each of the fuse assembly 156 and the temperature sensor assembly 158. The terminals 161 are connected to a control device (not shown).

The terminal assemblies 154 are provided adjacent to an inlet of the passageway 162 and upstream from the fuse assembly 156 and the temperature sensor assembly 158.

The heating assembly 152 includes a heating element 164 and a support member comprising a plurality of support rails 166 attached to the heating element 164. The support rails 166 each include an elongated body 168 and a pair of fingers 170 extending laterally from the elongated body 168. The fingers 170 clamp the heating element 164 therebetween. The support rails 166 are matingly inserted into slots 172 of the cylindrical wall 160. The slots 172 are formed on the inner surface 175 of the cylindrical wall 160 and extend along the length of the cylindrical wall 160.

The heating element 164 includes a coiled wire portion 174 and a pair of connecting portions 176 for connecting to the terminal assemblies 154. The connecting portions 176 may be in the form of nuts. When the heating assembly 154 is positioned inside the tubular housing 152, the connecting portions 176 are aligned with the terminal assemblies 154. By threading a screw 178 into a hole 179 of the cylindrical wall 160 and engaging the screw 178 to the nut-like connection portions 176, the terminal assemblies 154 are connected to the connecting portions 176.

Seventh Embodiment

Referring to FIG. 19, a heater 200 according to a seventh embodiment of the present disclosure includes a tubular housing 202 and a heating element 204 disposed around and outwardly of the tubular housing 202. The tubular housing 202 includes a cylindrical wall 206 and a support member comprising a plurality of fin elements 208 extending radially inwardly from an inner surface 201 of the cylindrical wall 206. The cylindrical wall 206 defines a fluid passageway 210. The plurality of fin elements 208 are integrally formed with the cylindrical wall 206 and are disposed in the fluid passageway 210. The cylindrical wall 206 and the fin elements 208 are made of aluminum.

The heating element 204 is coiled around the cylindrical wall 206 and contacts an outer surface of the cylindrical wall 206. The heating element 204 includes a resistive wire and an electrically insulating coating on the resistive wire. An outer surface of the cylindrical wall that is in contact with the heating element is coated with an electrically insulating layer 212.

A temperature sensor assembly 214 and a fuse assembly 216 are provided at each end of the tubular housing 202. The temperature sensor assemblies 214 monitor the temperature of the cylindrical wall 206 and consequently the fluid flowing therethrough. The fuse assembly 216 protects the heating element 204 from overheating.

Securing devices 220 are provided around the cylindrical wall 206 to secure the temperature sensor assembly 214 and the fuse assembly 216 on the tubular housing 202.

The heater 200 of this embodiment improves heat transfer efficiency by providing the plurality of fins elements 208 in the fluid passageway 210. While heat from the heating element 204 is transferred indirectly to the fluid through the tubular housing 202, the heater 200 has an advantage of increasing heat transfer efficiency by increasing surface area for heat transfer.

The flow-through heater of the present disclosure provides a simplified structure to facilitate manufacturing of the flow-through heater, resulting in reduced manufacturing costs. Moreover, the simplified structure of the flow-through heater improves heater transfer efficiency and reduces heat loss and can more quickly heat the fluid to a desired temperature. While the flow-through heater has been described as a heater for heating fluids to a desired temperature, the flow-through heater may be configured as a steam generator without departing from the scope of the present disclosure. The flow-through heaters of the present disclosure may be used in, for example, dishwaters, laundry machines, or a SPA water heating systems.

This description is merely exemplary in nature and, thus, variations that do not depart from the gist of the disclosure are intended to be included within the scope of the disclosure. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the description and specific examples, while indicating the preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of this disclosure. 

1. A flow-through heater comprising: a tubular housing defining a passageway; and a heating element provided in the passageway and attached to the tubular housing, the heating element including a resistive wire housed within an electrically insulating coating on the resistive wire, wherein the heating element further includes a coiled portion defining a channel extending in a direction along the longitudinal axis to enable a fluid to flow therethrough and contacting the fluid when the fluid flows through the channel.
 2. The flow-through heater of claim 1 wherein the passageway and the channel are coaxially aligned.
 3. The flow-through heater of claim 1 wherein the tubular housing comprises a cylindrical wall and a support member extending inwardly from the cylindrical wall and wherein the heating element is attached to the support element.
 4. The flow-through heater of claim 3 wherein the support member includes a plurality of fin elements extending radially inwardly from an inner surface of the cylindrical wall and extending a predetermined length along the longitudinal axis of the tubular housing.
 5. The flow-through heater of claim 3, further comprising a pair of terminal assemblies provided at the cylindrical wall.
 6. The flow-through heater of claim 5, wherein the terminal assemblies each include an insulating terminal housing inserted into an opening of the cylindrical wall.
 7. The flow-through heater of claim 6, wherein the cylindrical member is made of aluminum.
 8. The flow-through heater of claim 5, wherein the terminal assemblies each include a terminal housing integrally formed with the cylindrical wall.
 9. The flow-through heater of claim 8, wherein the terminal housing and the cylindrical wall are made of a plastic material.
 10. The flow-through heater of claim 1, wherein the fluid flows inside and outside the coiled portion of the heating element.
 11. The flow-through heater of claim 1, further comprising a support member for removably mounting the heating element to the tubular housing.
 12. The flow-through heater of claim 11, wherein the support member includes an elongated rail that is slidingly inserted in a slot of the cylindrical wall, the slot being formed on an inner peripheral surface of the cylindrical wall.
 13. The flow-through heater of claim 12, wherein the slot extends in a direction along the longitudinal axis of the tubular housing.
 14. The flow-through heater of claim 12, wherein the elongated rail comprises an elongated body and a pair of fingers extending laterally from the elongated body, the fingers securing the heating element therebetween.
 15. The flow-through heater of claim 1, wherein the tubular housing includes a cylindrical wall and a pair of hollow portions extending outwardly from the cylindrical wall for receiving at least one of a temperature sensor assembly and a fuse assembly.
 16. The flow-through heater of claim 15, wherein the hollow portions are integrally formed with the cylindrical wall.
 17. The flow-through heater of claim 15, wherein the cylindrical wall defines a pair of holes to enable a pair of terminal assemblies to pass through, the terminal assemblies including fasteners passing through the holes and the heating elements including connecting portions engaging a corresponding fastener.
 18. The flow-through heater of claim 1, wherein the cylindrical wall is a single-piece component.
 19. The flow-through heater of claim 1, wherein the cylindrical wall is a two-piece component.
 20. The flow-through heater of claim 1, further comprising an insulator provided between the cylindrical wall and the heating element to electrically insulate the heating element from the cylindrical wall.
 21. The flow-through heater of claim 20, wherein the insulator comprises a base portion extending in a direction along the longitudinal axis of the tubular housing and a pair of clamping legs extending from the base portion in a first direction toward the support member, the base portion engaging the heating element, the pair of clamping legs defining a slot for receiving the support member.
 22. The flow-through heater of claim 21, wherein the clamping legs extend an entire length of the base portion.
 23. The flow-through heater of claim 21, wherein each of the insulators further includes a pair of fingers extending from the base portion in a second direction and wherein the second direction is opposite to the first direction.
 24. The flow-through heater of claim 1, wherein the heating element contacts a peripheral inner surface of the tubular housing and is mounted to the tubular housing in an interference-fit manner.
 25. The flow-through heater of claim 1, wherein the tubular housing further comprises a cylindrical wall and a pair of hollow portions extending outwardly from an outer peripheral surface of the cylindrical wall, wherein the hollow portions are integrally formed with the cylindrical wall.
 26. The flow-through heater of claim 25, wherein the heating element further comprises a pair of connecting portions extending from the coiled portion, wherein the connecting portions extend through the hollow portions.
 27. The flow-through heater of claim 26, further comprising a potting material that fills cavities of the hollow portions and that electrically insulates a part of the connecting portions.
 28. The flow-through heater of claim 27, further comprising a pair of terminal pins extending through the hollow portions, wherein the heating element is connected to a power source through the terminal pins.
 29. A flow-through heater comprising: a cylindrical wall extending along a longitudinal axis and defining a passageway to allow a fluid to flow therethrough; a fin element extending inwardly from an inner surface of the cylindrical wall and in the passageway; a heating element provided in the passageway and attached to the fin element, the heating element including a resistive wire housed within an electrically insulating coating, the heating element including a coiled wire portion that defines a channel coaxially aligned with the passageway, the fluid flowing inside and outside the coiled wire portion; a pair of terminal assemblies that connect the heating element to a power source, the terminal assemblies each including a terminal housing at the cylindrical wall and a terminal pin inserted through the terminal housing, the terminal pin connecting the heating element to the power source; and a potting material provided in the terminal assemblies to embed a portion of the terminal pin therein.
 30. A flow-through heater comprising: an outer wall including an inner peripheral surface, the inner peripheral surface defining a passageway along a longitudinal axis of the outer wall; a plurality of fin elements located in the passageway and extending inwardly from the inner peripheral surface; and a heating element provided on an outer peripheral surface of the outer wall.
 31. The flow-through heater of claim 30, wherein the heating element includes a resistive wire coiled around the outer wall and an electrically insulating coating on the resistive wire.
 32. The flow-through heater of claim 30, wherein the outer wall is cylindrical in shape and made from a metal material and includes an outer peripheral surface and an insulating coating on the outer peripheral surface, the heating element being wrapped around the outer peripheral surface. 